Embodiments of systems and methods model and generate open reusable, business components for Service Oriented Architectures (SOAs) from existing client / server applications. Applications are decomposed into business component frameworks with separate user interface, business logic, and event management layers to enable service-oriented development of new enterprise applications. Such layers are re-assembled through an open standards-based, Native Application Services (NAS) to render similar or near identical transactional functionality within a new application on an open platform, without breaking former production code, and without requiring a change in an end-user's business processes and / or user experience. In addition, the same separated layers may form re-usable business components at any desired level of granularity for re-use in external composite applications through industry-standard interfaces, regardless of usage, context, or complexity in the former Client / Server application.